Light-Emitting Diode (LED) Module with Light Sensor Configurations for Optical Feedback

ABSTRACT

An embodiment of the disclosure includes a LED module. A substrate is provided. A light sensor is positioned in the substrate. A LED chip is attached to the substrate. The LED chip has a first side and a second side. The second side is covered by an opaque layer with an opening. The opening is substantially aligned with the light sensor. The light sensor receives a light output emitting from the LED chip through the opening.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. patentapplication Ser. No. 12/881,566, filed Sep. 14, 2010, now allowed, thecontents of which is hereby incorporated herein by express referencethereto.

TECHNICAL FIELD

The disclosure relates generally to a Light-Emitting Diode (LED) module,and more particularly to an LED module having specific light sensorconfigurations for optical feedback.

BACKGROUND

A Light-Emitting Diode (LED), as used herein, is a semiconductor lightsource for generating a light at a specified wavelength or a range ofwavelengths. LEDs are traditionally used for indicator lamps, and areincreasingly used for displays. An LED emits light when a voltage isapplied across a p-n junction formed by oppositely doped (and typicallycompound) semiconductor layers. Different wavelengths of light can begenerated using different materials by varying the bandgaps of thesemiconductor layers and by fabricating an active layer within the p-njunction.

LEDs are semiconductor based. For a given drive current, light outputvaries from chip to chip, and also varies over the life of each chip.Light output also varies inversely with temperature, but not uniformlyfor each color. Finally, in a block of LEDs of a given color, the lightoutput will vary if one or more of the LEDs fails. Given all the factorswhich can affect the color balance of any array of LEDs, it would bedesirable to automatically monitor and regulate the color balance,especially in a white-light emitting module.

In an array of LEDs of the same color, for example a traffic light,variations in light output based on temperature can be compensated byvarying the current supplied to the array. This scheme would becumbersome in a module having LEDs in a plurality of colors, because thevariation in light output due to temperature is not the same for thevarious colors.

It would be desirable to be able to compensate for the differenttemperature variations in output in a multicolor array of LEDs. Forexample, it would be desirable to automatically control the chromaticityof a white light emitting module comprising red, blue and green LEDs,without regard to the factors which cause the light outputs of theindividual colors to vary.

It would further be desirable to automatically control the variation ofeach color LED without resorting to a spectrally resolving lightmeasuring system, such as a photodiode and filter, for each of therespective colors.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale. In fact, thedimensions of the various features may be arbitrarily increased orreduced for clarity of discussion.

FIGS. 1 and 2 are flowcharts of methods for fabricating Light-EmittingDiode (LED) modules according to embodiments of the disclosure.

FIGS. 3 to 7 and 8 a, 8A, 8 b, 8B, 8 c, and 8C are cross-sectional viewsof LED modules at various stages of manufacture according to FIGS. 1 and2.

FIGS. 9 and 10 are diagrams of methods for operation of a LED modulewith optical feedback and control portion.

DETAILED DESCRIPTION

The making and using of illustrative embodiments are discussed in detailbelow. It should be appreciated, however, that the disclosure providesmany applicable inventive concepts that can be embodied in a widevariety of specific contexts. The specific embodiments discussed aremerely illustrative and do not limit the scope of the invention.

Illustrated in FIGS. 1 and 2 are flowcharts of methods 11 and 12 forfabricating Light-Emitting Diode (LED) modules according to embodimentsof the disclosure. FIG. 1 illustrates generalized steps that areperformed with various embodiments of the disclosure. FIG. 2 illustratesdifferent embodiments that include the generalized steps of FIG. 1.FIGS. 3 to 8 are cross-sectional views of LED modules at various stagesof manufacture according to FIGS. 1 and 2. FIGS. 9 and 10 are flowchartsillustrating the method of operation of a LED module with opticalfeedback and control in accordance with this disclosure.

An LED module may be a part of a display or lighting device having anumber of modules, the LEDs in each module being either controlledsingly or in combination. The LED may also be a part of an integratedcircuit (IC) chip, system on chip (SoC), or portion thereof, that mayinclude various passive and active microelectronic devices such asresistors, capacitors, inductors, diodes, metal-oxide semiconductorfield effect transistors (MOSFETs), complementary metal-oxidesemiconductor (CMOS) transistors, bipolar junction transistors (BJTs),laterally diffused MOS (LDMOS) transistors, high power MOS transistors,or other types of transistors. It is understood that various figureshave been simplified for a better understanding of the inventiveconcepts of the present disclosure. Accordingly, it should be noted thatadditional processes may be provided before, during, and after themethods of FIGS. 1 and 2. Some other processes may only be brieflydescribed, and various known processes may be substituted for thedescribed processes to achieve the same effect.

Referring to FIG. 1 and FIG. 3, in process step 13, a substrate 101 isprovided. The substrate 101 refers to a semiconductor substrate on whichvarious layers and integrated circuit components are formed. Thesubstrate 101 may comprise silicon or a compound semiconductor, such asGaAs, InP, Si/Ge, or SiC. Examples of layers may include dielectriclayers, doped layers, metal layers, polysilicon layers and via plugsthat may connect one layer to one or more layers. Examples of integratedcircuit components may include transistors, resistors, and/orcapacitors. The substrate 101 may be part of a wafer that includes aplurality of semiconductor dies fabricated on the surface of thesubstrate, wherein each die comprises one or more integrated circuits.The plurality of semiconductor dies are divided by scribe lines (notshown) between the dies.

Referring to FIG. 1 and FIG. 3, in process step 15, a light sensor 103is formed in the substrate 101. The light sensor 103 has a width W1. Inone embodiment, the light sensor 103 may be disposed over a top surfaceof the substrate 101 and extended into the substrate 101. In anotherembodiment, the light sensor 103 may be disposed above the top surfaceof the substrate 101. The light sensor 103 may include a light-sensingregion which may be a doped region having N-type and/or P-type dopantsformed in the substrate 101 by a method such as diffusion or ionimplantation. The light-sensing region detects light that shines on it.The light sensor 103 may include photosensitive diodes or photodiodesfor recording an intensity or brightness of light on the diode.Connections to the light-sensing region may comprise interconnectregions in the substrate 101 to TSV connections extending through thesubstrate 101.

Referring to FIG. 1 and FIG. 4, in process step 17, a LED chip isprovided. The LED chip is fabricated on a growth substrate 105, andincludes a material that is suitable for growing a light-emittingstructure 109. In one embodiment, the growth substrate 105 is sapphire.In other embodiments, the growth substrate 105 may be silicon carbide,silicon, gallium nitride, or another suitable material for growing thelight-emitting structure 109.

Referring to FIG. 4, a buffer layer 107, often comprising galliumnitride or aluminum nitride, is grown on the growth substrate 105 in anepitaxial growth processes. The buffer layer may be about 500 nm to 5pm, for example, about 2 pm. A light-emitting structure 109 is formedover the buffer layer. The light-emitting structure 109 is usually asemiconductor diode. In the present embodiment, the light-emittingstructure 109 includes a doped layer 111, a multiple quantum well layer(MQW) 113, and a doped layer 115. The doped layers 111 and 115 areoppositely doped semiconductor layers. In some embodiments, the dopedlayer 111 includes an n-type gallium nitride material, and the dopedlayer 115 includes a p-type gallium nitride material. In otherembodiments, the doped layer 111 may include a p-type gallium nitridematerial, and the doped layer 115 may include an n-type gallium nitridematerial. The MQW layer 113 shown in FIG. 4 includes alternating (orperiodic) layers of two different compound semiconductor materials, forexample, gallium nitride and indium gallium nitride. For example, in oneembodiment, the MQW layer 113 includes ten layers of gallium nitride andten layers of indium gallium nitride, where an indium gallium nitridelayer is formed on a gallium nitride layer, and another gallium nitridelayer is formed on the indium gallium nitride layer, and so on and soforth. The light emission efficiency of the structure 109 depends on thenumber of alternating layers and thicknesses of those layers. Thethickness of the MQW layer 113 may be about 10-2000 nm, about 100-1000nm, about 1 μm, or about 100 nm, for example.

In FIG. 4, the doped layer 111, the MQW layer 113, and the doped layer115 are all formed by epitaxial growth processes. The layers 111, 113and 115 are epitaxially grown on the buffer layer 107. The doping may beaccomplished by adding impurities into a source gas during the epitaxialgrowth process or by other commonly used doping processes. After thecompletion of the epitaxial growth process, a p-n junction (or a p-ndiode) is essentially formed in the MQW layer 113 between the dopedlayer 111 and the doped layer 115. When an electrical voltage is appliedbetween the doped layer 111 and the doped layer 115, electrical currentflows through the light-emitting structure 109 and the structure 109emits radiation. The color of the light emitted by the structure 109 isdetermined by the wavelength of the emitted radiation, which may be“tuned” (or selected) by varying the composition and structure of thematerials that make up the structure 109. For example, a small increasein the concentration of indium in the indium gallium nitride layer inthe MQW 113 is associated with a shift of the light's wavelength outputtoward longer wavelengths.

Referring to FIG. 5, a contact layer 117 is formed on the light-emittingstructure 109. The contact layer 117 may be added on the doped layer 115to form an ohmic contact. Then, a mesa structure 110 is defined byphotolithography patterning processes and etching processes. The mesastructure 110 is etched from the top surface of the contact layer 117 toexpose a middle portion of the doped layer 111.

A light reflecting layer 119 is formed on the contact layer 117 and theexposed surface of the doped layer 111. Then, the light reflecting layer119 is patterned by photolithography patterning processes and etchingprocess to form an opening 112 with a width W2 in the light reflectinglayer 119 and a contact portion 121 on the exposed surface of the dopedlayer 111. Consequently, a LED chip 10 is formed. The process step 17 inFIG. 1, a LED chip 10 with one side of the LED chip 10 covered by theopaque layer 119 with the opening 112, is provided. The light reflectinglayer 119 is an opaque layer and may reflect the radiation emitting fromthe light-emitting structure 109. The light reflecting layer 119 may bea metal, such as aluminum, copper, titanium, silver, gold, alloys ofthese such as titanium/platinum/gold, or combinations thereof.Particularly, silver and aluminum are known to be good reflectors ofblue light. The light-reflecting layer 119 may be formed by a physicalvapor deposition (PVD) process, a chemical vapor deposition (CVD), anelectroplating process, or other deposition processes. Additional layersmay be optionally formed not shown in FIG. 5. For example, an indium tinoxide (ITO) layer, or another transparent conductive layer may beformed.

Referring to FIG. 1 and FIG. 6, in process step 19, the LED chip 10shown in FIG. 5 is attached to the substrate 101 to form a LED component100. The opening 112 is substantially aligned with the light sensor 103in the substrate 101. The LED chip 10 is flipped over and bonded to thesubstrate 101 by using a solder 123 for electrical connection. In theembodiment shown in FIG. 6, the width W1 of the light sensor 103 iswider than the width W2 of the opening 112. In other embodiments, thewidth W2 may be equal to or greater than W 1, but the smaller the widthW2 of the opening 112 the more light is reflected upward. A light outputemitting from the MQW layer 113 of the LED chip 10 through the opening112 is collected by the light sensor 103. The majority of the lightoutput from the MQW layer 113 is reflected upward by the lightreflecting layer 119. The distance between the opening 112 and the lightsensor 103 is small. Hence, the light output could be collected withoutany interference.

Referring to FIG. 7, another embodiment of the LED component 100 isshown. The layers stack of the LED chip is similar to FIG. 5 except thatlight reflecting layer 119 is formed on the bottom surface of thesubstrate 105 and a contact portion 125 is formed over the contact layer117. The LED chip 10 is bonded to the substrate 101 by using an adhesivematerial 129. A wire 127 electrically contacts the contact portion 125and the substrate 101 to provide electrical connection between the LEDchip 10 and the substrate 101. The opening 112 in the reflecting layer119 is substantially aligned with the light sensor 103 in the substrate101. In the embodiment shown in FIG. 7, the width W1 of the light sensor103 is wider than the width W2 of the opening 112. A light outputemitting from the MQW layer 113 of the LED chip penetrating through theopening 112 is collected by the light sensor 103.

Referring to FIG. 1 and FIG. 8 a, in process step 21, the substrate 101portion of the LED component 100 is attached to a circuit board 201. Thecircuit board 201 electrically connects to the LED chip 10 and thesensor 103 through interconnects in the substrate 101. For the sake ofsimplicity and brevity, the LED component 100 is shown as a simple chipwithout further details. In one embodiment, the circuit board 201 mayinclude package substrate, printed circuit board or any suitablecomponent being familiar to those skilled in the art.

Referring to FIG. 1 and FIG. 8 a, in process step 23, the LED chip 10 ofLED component 100 is covered with a lens 203 to form a LED module 1001.The lens 203 may be formed by inserting a lens glue or molding materialinto a mold cavity covering the LED component 100. The lens glue iscured so that it retains its shape and adheres to the circuit board 201and the LED component 100. In one embodiment, the lens 203 comprises aphosphor material to generate a specific color. To generate white lightfrom the LED module 1001, at least one phosphor material is used. Forexample, a white light may be generated using a blue LED chip withyellow phosphor or with a red phosphor and green phosphsor.

Referring to FIG. 8A, another embodiment of the LED module 1001 isshown. The LED module 1001 comprises the LED component 100 covered bythe lens 203 and a second light sensor 205 positioned on the circuitboard 201 not underneath the LED chip 10. In one embodiment, the secondlight sensor 205 is not covered by the lens 203. A light output with afirst wavelength emitting from the light—emitting structure 109 of theLED chip 10 through the opening 112 is collected by the light sensor103. The light output with the first wavelength excites the phosphormaterial in the lens 203 to convert the light output with a secondwavelength. The light output with the second wavelength emitting out theLED component 100 is collected by the second light sensor 205.

Referring to FIG. 2, method 12 illustrates different embodiments thatinclude the generalized steps of the method 11 in FIG. 1. The method 12for fabricating Light-Emitting Diode (LED) modules begins at step 15 a,which is the same as the process step 13 and 15 in the method 11. Afirst light sensor is provided on a first substrate.

Next, the process step 17 a of method 12, which is the same as theprocess step 17 in method 11, is performed. A first LED chip with oneside of the first LED chip covered by a first opaque layer with a firstopening is provided. The cross-sectional views at various stages of theprocess step 17 a are illustrated in FIGS. 4 to 5.

Then, the process step 19 a of method 12, which is the same as theprocess step 19 in method 11, is performed. The first LED chip isattached to the first substrate to form a first LED component. The firstopening in the first opaque layer is substantially aligned with thefirst light sensor. Different embodiments of cross-sectional views ofthe process step 19 a are illustrated in FIGS. 6 and 7.

The process steps 15 b to 19 b form a second LED component. The step 15b to 19 b repeat step 15 a to 19 a on the second LED component. In step15 b, a second light sensor is provided on a second substrate.

Next, the process step 17 b of method 12, a second LED chip with oneside of the second LED chip covered by a second opaque layer with asecond opening is provided. The cross-sectional views at various stagesof the process step 17 b are illustrated in FIGS. 4 to 5. The first LEDchip and the second LED chip emit different colors. The details of thefirst LED chip and the second LED chip will be introduced later.

Then, in the process step 19 b of method 12, the second LED chip isattached to the second substrate to form the second LED component. Thesecond opening in the second opaque layer is substantially aligned withthe second light sensor. Different embodiments of cross-sectional viewsof the process step 19 b are illustrated in FIGS. 6 and 7.

The method 12 continues to process step 21′. The first substrate of thefirst LED component and the second substrate of the second LED componentare attached to a circuit board.

Next, method 12 continues to process 23′. The first LED chip of thefirst LED component and the second LED chip of the second LED componentare covered by one or more lens to form a LED module.

FIGS. 8 b to FIGS. 8C illustrate various embodiments of cross-sectionalviews for the LED module formed by the method 12. The details of a firstLED component 100 a, a second LED component 100 b and a third LEDcomponent 100 c are the same as the LED component 100 shown in FIGS. 6and 7.

Referring to FIG. 8 b, a first substrate 101 a of the first LEDcomponent 100 a and a second substrate 101 b of the second LED component100 b are attached to a circuit board 201. The first LED component 100 aand the second LED component 100 b are covered with a lens 203. In oneembodiment, the lens 203 comprises a phosphor material. In otherembodiment, the lens 203 does not comprise phosphor materials.

In this embodiment, a first LED chip 10 a of the first LED component 100a and a second LED chip 10 b of the second LED component 100 b emitdifferent colors. The surface of first LED chip 10 a may be covered by aphosphor material 202 to emit a first color. The second LED chip 10 b,that maybe free of phosphor material, emits a second color. The firstcolor and the second color combine to form a third color. For example,the first LED component 100 a may include a blue LED chip covered with ayellow phosphor, and the second LED component 100 b may include a redLED chip so that the combined output of the chips forms a white color.

Referring to FIG. 8B, another embodiment of the LED module 1001 isshown. The first LED component 100 a and the second LED component 100 bare attached to the circuit board 201 and covered by the lens 203. Asecond light sensor 205 not underneath either the first LED chip 10 a orthe second LED chip 10 b is positioned on the circuit board 201. In oneembodiment, the second light sensor 205 is not covered by the lens 203.The first LED chip 10 a of the first LED module 100 a may be covered bythe phosphor material 202 on the surface of the first LED chip 10 a toemit a first color. The second LED chip 10 b of the second LED module100 b, that maybe free of phosphor material, emits a second color. Thefirst color and the second color combine to form a third color, which isdetected by the second light sensor 205.

Referring to FIG. 8 c, another embodiment of the LED module 1001 isshown. The first LED component 100 a, the second LED component 100 b,and the third LED component 100 c are attached to the circuit board 201and covered by the lens 203. The first LED chip 10 a of the first LEDcomponent 100 a, the second LED chip 10 b of the second LED component100 b, and the third LED chip 10 c of the third LED component 100 c emita first color, a second color and a third color, respectively. In oneembodiment, the first color, the second color and the third color aredifferent. The first color, the second color, and the third color arecombined to form a fourth color. For example, blue, red and green arecombined to form white. In other embodiment, the first LED chip 10 a ofthe first LED module 100 a may be covered by a phosphor material on thesurface of the first LED chip 10 a to emit a first color. The second LEDchip 10 b and the third LED chip 10 c, which may be free of phosphormaterial, emit a second color. The second LED 10 b chip and the thirdLED chip 10 c do not turn on at the same time. One of the second LEDchip 10 b and the third LED chip 10 c is turned on while the other isused as a spare. The first color and the second color are combined toform a third color. For example, the blue chip covered with yellowphosphor may combine with a red chip to form a white color.

Referring to FIG. 8C, another embodiment of the LED module 1001 isshown. The first LED component 100 a, the second LED component 100 b,and the third LED component 100 c are attached to the circuit board 201and covered by the lens 203. A second light sensor 205 not underneathany of the first LED chip 10 a, the second LED chip 10 b or the thirdLED chip 10 c is positioned on the circuit board 201. In one embodiment,the second light sensor 205 is uncovered by the lens 203. The first LEDchip 10 a of the first LED component 100 a, the second LED chip 10 b ofthe second LED component 100 b, and the third LED chip 10 c of the thirdLED component 100 c emit a first color, a second color and a thirdcolor, respectively. In one embodiment, the first color, the secondcolor, and the third color are different. The first color, the secondcolor, and the third color are combined to form a fourth color, which isdetected by the second light sensor 205. For example, blue, red andgreen are combined to form white.

FIGS. 9 and 10 are diagrams of methods 300 and 400 for operating a LEDmodule with optical feedback and control. FIGS. 8A, 8B and 8C illustratevarious embodiments of cross-sectional views for the LED module that maybe operated by the method 300. FIGS. 8 b and 8 c illustrate variousembodiments of cross-sectional views of LED modules that may be operatedby the method 400.

The method 300 for operating an LED module begins at step 301. The LEDmodule 1001 shown in FIG. 8A is provided as an example. The LED module1001 comprises at least one LED component 100, which is attached to acircuit board 201. The LED component 100 comprises a LED chip 10 asshown in FIG. 5 and a first light sensor 103 underneath the LED chip 10in a first substrate 101. One side of the LED chip 10 is covered by anopaque layer 119 with an opening 112. The opening 112 is substantiallyaligned with the first light sensor 103. The circuit board 201 comprisesa second light sensor 205 not underneath the LED chip 10. The LEDcomponent 100 is covered by a lens 203 and the second light sensor 205on the circuit board 201 is not covered by the lens 203. In oneembodiment, the lens 203 comprises a phosphor material.

At step 303 in FIG. 9, a measurement sequence is initiated when thepower is turned on and provided to the LED module 1001.

At step 305 in FIG. 9, a light output with a first wavelength, or afirst color, is emitted from the LED chip 10. Then, the light outputwith the first wavelength excites the phosphor material in the lens 203to convert the light output with a second wavelength, or a second color.The light output with the second wavelength, or the second color, emitsfrom the LED module 1001. For example, the LED chip 10 emitting bluelight excites yellow phosphor to convert the light output from the LEDmodule 1001 to white light.

At step 307 in FIG. 9, the light output with the first wavelength, orthe first color emitting from the LED chip 10 that penetrates throughthe opening 112, is collected by the first light sensor 103. The lightoutput with the second wavelength, or the second color emitting from theLED module 1001, is collected by the second light sensor 205. Thedistance between the opening 112 and the first light sensor 103 issmall. Hence, the light output with the first wavelength from theopening 112 is collected by the first light sensor 103 accurately. Thelight output with the first wavelength and the second wavelength arecollected by the first light sensor 103 and the second light sensor 205respectively. The lights of the different wavelengths do not interferewith each other. As described in a previous example, blue light would bedetected by the first light sensor 103 and white light would be detectedby the second light sensor 205.

At step 308 in FIG. 9, predetermined desired settings for the lightoutput of the first wavelength and the second wavelength are stored in astorage apparatus.

At step 309 in FIG. 9, the light output with the first wavelength andthe second wavelength collected by the first light sensor 103 and thesecond light sensor 205 are compared with the predetermined desiredsettings.

At step 311 in FIG. 9, a comparison is made to determine whether thelight output with the first wavelength collected by the first lightsensor 103 matches the predetermined desired settings. As with thepreviously described examples, blue light detected by the first lightsensor 103 is measured to determine whether it matches predetermineddesired settings or not. If the detected light matches the predetermineddesired setting, the process continues to step 315. If the detectedlight does not match the predetermined desired setting, an adjustment ismade at a step 313 to alter an electrical current to the LED component100 for better achieving the setting for the first wavelength, and themeasuring sequence step 303 is repeated.

At step 315 in FIG. 9, a comparison is made to determine whether thelight output of the second wavelength collected by the second lightsensor 205 matches the predetermined desired settings. As with thepreviously described examples, white light detected by the second lightsensor 205 is measured to determine whether it matches predetermineddesired settings or not. If the detected light matches the predetermineddesired setting, the process continues by returning to the measuringsequence step 303. If the detected light does not match thepredetermined desired setting, an adjustment is made at a step 313 toalter the electrical current to the LED component 100 for betterachieving the setting for the second wavelength and the measuringsequence step 303 is repeated.

In FIG. 10, the method 400 for operating an LED module begins at step401. The LED module 1001 shown in FIG. 8 b is provided as an example.The LED module 1001 comprises at least two LED components, such as afirst LED component 100 a and a second LED component 100 b. The at leasttwo LED components are attached to a circuit board 201. Each of the atleast two LED components emit different color. Each of the LEDcomponents comprises a LED chip 10 as shown in FIGS. 5 and 6, and alight sensor 103 in a substrate 101. One side of each LED chip 10 iscovered by an opaque layer 119 with an opening 112. The opening 112 issubstantially aligned with the light sensor 103. The first LED component100 a and the second LED component 100 b are covered by a lens 203. Inone embodiment, the surface of the LED chip 10 is covered by a phosphormaterial.

At step 403 in FIG. 10, a measurement sequence is initiated when thepower to the circuit board 201 is turned on and provided to the LEDmodule 1001.

At step 405 in FIG. 10, a light output with a wavelength or a coloremits from each LED chip 10 of at least two LED components 100 a and 100b. Each LED chip of the at least two LED components emits differentcolor.

At step 407 in FIG. 10, the light output with the wavelength or thecolor emitting from each LED chip 10 that penetrates through the opening112 is collected by each of the light sensors 103 of each LED component,respectively. For each LED component, the distance between the opening112 and the light sensor 103 is small. Hence, the light output fromdifferent LED chips will not interfere each other. The light output fromeach LED chip could be collected by the respective light sensor 103accurately.

At step 408 in FIG. 10, predetermined desired settings for the lightoutput of each LED chip in each LED component are stored in a storageapparatus.

At step 409 in FIG. 10, the light output of each LED chip with thewavelength collected by the light sensor 103 in each LED component arecompared with the predetermined desired settings.

At step 411 in FIG. 10, a comparison is made to determine whether thelight output of each LED chip with the wavelength collected by the lightsensor 103 in each LED component matches the predetermined desiredsetting. If the detected light matches the predetermined desiredsetting, the process continues to the measuring sequence step 403. Ifthe detected light does not match the predetermined desired setting, anadjustment is made at step 413 to alter an electrical current to eachLED component for better achieving the setting for the wavelength andthe measuring sequence step 403 is repeated.

Although the embodiments and its advantages have been described indetail, it should be understood that various changes, substitutions andalterations can be made herein without departing from the spirit andscope of the invention as defined by the appended claims. Moreover, thescope of the present application is not intended to be limited to theparticular embodiments of the process, machine, manufacture, andcomposition of matter, means, methods and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed:
 1. An apparatus, comprising: a substrate; alight-sensing element disposed in the substrate; and a light-emittingdiode (LED) chip disposed over, and electrically coupled to, thesubstrate, the LED chip containing a light-emitting layer and alight-reflective layer disposed between the light-emitting layer and thesubstrate, wherein the light-reflective layer includes an opening thatis aligned with the light-sensing element.
 2. The apparatus of claim 1,wherein the light-sensing element includes a photodiode.
 3. Theapparatus of claim 1, wherein the LED chip further comprises: a firstdoped semiconductor layer and a second doped semiconductor layerdisposed on opposite sides of the light-emitting layer, the first andsecond doped semiconductor layers having different types ofconductivity; and a growth substrate coupled to one of the first andsecond doped semiconductor layers.
 4. The apparatus of claim 3, whereinthe MQW layer is disposed between the growth substrate and thelight-reflective layer.
 5. The apparatus of claim 3, wherein the growthsubstrate is disposed between the MQW layer and the light-reflectivelayer.
 6. The apparatus of claim 1, wherein the light-sensing element iswider than the opening.
 7. The apparatus of claim 1, wherein: thesubstrate includes a first side and a second side opposite the firstside; the LED chip is disposed over the first side of the substrate; andthe light-sensing element is disposed near the first side.
 8. Theapparatus of claim 7, further comprising: a circuit board attached tothe second side of the substrate; and a lens disposed over the circuitboard, wherein the substrate and the LED chip are housed within thelens.
 9. The apparatus of claim 8, further comprising a further lightsensor disposed over the circuit board and outside of the lens.
 10. Theapparatus of claim 8, further comprising: a further LED chip disposedover the circuit board and housed within the lens, wherein the LED chipand the further LED chip are configured to emit different colors oflight.
 11. A method, comprising: forming a light-sensing element in asubstrate; providing a light-emitting diode (LED) chip, the LED chipincluding: a first doped semiconductor layer and a second dopedsemiconductor layer having different types of conductivity; alight-emitting layer disposed between the first doped semiconductorlayer and the second doped semiconductor layer; and a light-reflectivelayer configured to reflect light emitted by the light-emitting layer,the light-reflective layer having an opening; and bonding the LED chipto the substrate in a manner such that the opening of thelight-reflective layer is aligned with the light-sensing element. 12.The method of claim 11, wherein the bonding the LED chip comprisesbonding the LED chip through solder bumps.
 13. The method of claim 11,wherein the bonding the LED chip comprises a wire bonding process. 14.The method of claim 11, further comprising: attaching the substrate to acircuit board, wherein the circuit board and the LED chip are disposedon different sides of the substrate; and forming a lens over the circuitboard, the lens covering the LED chip and the substrate.
 15. The methodof claim 14, further comprising: forming a further light sensor over anarea of the circuit board outside of the lens.
 16. The method of claim14, further comprising: providing a further LED chip; bonding thefurther LED chip to a further substrate; and attaching the further LEDchip to the circuit board through the further substrate; wherein: thefurther LED chip is housed within the lens; and the LED chip and thefurther LED chip are configured to emit different colors of light.
 17. Amethod, comprising: providing a light-emitting diode (LED) module thatcontains a circuit board and one or more LED components located over thecircuit board, wherein each LED component includes an LED chip bonded toa substrate having an embedded light sensor; sensing a first light and asecond light emitted by the LED module, the first light having a firstwavelength and the second light having a second wavelength; comparingthe first wavelength and the second wavelength to a predetermined targetfirst wavelength and a predetermined target second wavelength; andadjusting an electrical current driving the one or more LED componentsbased on the comparing.
 18. The method of claim 17, wherein: the one ormore LED components include a first LED component and a second LEDcomponent; the first light is emitted by a first LED chip and sensed bya first light sensor of the first LED component; and the second light isemitted by a second LED chip and sensed by a second light sensor of thesecond LED component.
 19. The method of claim 17, wherein: the LEDmodule further includes a non-embedded light sensor disposed over thecircuit board; the first light is emitted by the LED chip and sensed bythe embedded light sensor of one of the LED components; and the secondlight is emitted by one of the LED components and sensed by thenon-embedded light sensor.
 20. The method of claim 17, wherein each LEDchip includes a light-reflective layer with an opening that is alignedwith the embedded light sensor.